Come into one of its 1,400 stores that do trade-ins and turn in a working iPhone 4s or iPhone 5 and you will get a $150 minimum trade-in that can be used to get the iPhone 5s 16GB model ($149.99) for free.

Customers must be eligible for an upgrade and activate a two-year contract with AT&T, Sprint or Verizon. The offer is good for Friday and Saturday, Feb. 28 and March 1.

Getting a steady stream of customers in the door is important for Best Buy, which on Thursday announced that its fourth quarter earnings were better than expected. However, profit arose from cost cutting not sales.